The critical points are x=2, x=3, and x=4. We will consider the following cases: In this case, x−2≤0, x−3≤0, and x−4≤0. Thus ∣x−2∣=2−x, ∣x−3∣=3−x, and ∣x−4∣=4−x. The equation becomes:
(2−x)+(3−x)+2(4−x)=9 2−x+3−x+8−2x=9 Since 1≤2, x=1 is a valid solution. Case 2: 2<x≤3 In this case, x−2>0, x−3≤0, and x−4≤0. Thus ∣x−2∣=x−2, ∣x−3∣=3−x, and ∣x−4∣=4−x. The equation becomes:
(x−2)+(3−x)+2(4−x)=9 x−2+3−x+8−2x=9 Since 2<x≤3, x=0 is not a valid solution. Case 3: 3<x≤4 In this case, x−2>0, x−3>0, and x−4≤0. Thus ∣x−2∣=x−2, ∣x−3∣=x−3, and ∣x−4∣=4−x. The equation becomes:
(x−2)+(x−3)+2(4−x)=9 x−2+x−3+8−2x=9 This is a contradiction, so there are no solutions in this case.
In this case, x−2>0, x−3>0, and x−4>0. Thus ∣x−2∣=x−2, ∣x−3∣=x−3, and ∣x−4∣=x−4. The equation becomes:
(x−2)+(x−3)+2(x−4)=9 x−2+x−3+2x−8=9 4x−13=9 x=422=211=5.5 Since 5.5>4, x=5.5 is a valid solution.